Using Enterprise Server with a load balancer

A load balancer design uses a network device to direct Git and HTTP traffic to individual Enterprise Server appliances. You can use a load balancer to restrict direct traffic to the appliance for security purposes or to redirect traffic if needed without DNS record changes. We strongly recommend using a TCP-based load balancer that supports the PROXY protocol.

DNS lookups for the Enterprise Server hostname should resolve to the load balancer. We recommend that you enable subdomain isolation. If subdomain isolation is enabled, an additional wildcard record (*.HOSTNAME) should also resolve to the load balancer. For more information, see Enabling subdomain isolation.

Because client connections to Enterprise Server come from the load balancer, the client IP address can be lost.

If your load balancer can support it, we strongly recommend implementing the PROXY protocol. When no PROXY support is available, it is also possible to load balance the HTTP and HTTPS ports using the X-Forwarded-For header.

We strongly recommend enabling PROXY protocol support for both your instance and the load balancer. Use the instructions provided by your vendor to enable the PROXY protocol on your load balancer. For more information, see the PROXY protocol documentation.

1. From an administrative account on Enterprise Server, in the upper-right corner of any page, click .

2. If you're not already on the "Site admin" page, in the upper-left corner, click Site admin.

3. In the " Site admin" sidebar, click Management Console.

4. In the "Settings" sidebar, click Privacy and uncheck Private mode.

5. Under "External load balancers", select Enable support for PROXY protocol.

6. Under the "Settings" sidebar, click Save settings.

   Note

   Saving settings in the Management Console restarts system services, which could result in user-visible downtime.

7. Wait for the configuration run to complete.

Use the X-Forwarded-For protocol only when the PROXY protocol is unavailable. The X-Forwarded-For header is compatible with HTTP and HTTPS only. For Git connections over SSH, the IP address reported will be that of the load balancer. In some environments, client IP addresses in the instance's audit log may incorrectly appear as 127.0.0.1.

1. From an administrative account on Enterprise Server, in the upper-right corner of any page, click .

2. If you're not already on the "Site admin" page, in the upper-left corner, click Site admin.

3. In the " Site admin" sidebar, click Management Console.

4. In the "Settings" sidebar, click Privacy and uncheck Private mode.

5. Under External load balancers, select Allow HTTP X-Forwarded-For header.

6. Under the "Settings" sidebar, click Save settings.

   Note

   Saving settings in the Management Console restarts system services, which could result in user-visible downtime.

7. Wait for the configuration run to complete.

Health checks allow a load balancer to stop sending traffic to a node that is not responding if a pre-configured check fails on that node. If the instance is offline due to maintenance or unexpected failure, the load balancer can display a status page. In a High Availability (HA) configuration, a load balancer can be used as part of a failover strategy. However, automatic failover of HA pairs is not supported. You must manually promote the replica instance before it will begin serving requests. For more information, see Configuring high availability.

Configure the load balancer to check the following URL.

http(s)://HOSTNAME/status

The endpoint will return status code 200 (OK) if the node is healthy and available to service end-user requests. For more information, see Monitoring a high-availability configuration.

If you cannot connect to services on your Enterprise Server instance through a load balancer, you can review the following information to troubleshoot the problem.

If you enable support for the X-Forwarded-For header on your instance and load balancer, you may not be able to access your instance's Management Console. For more information about the Management Console and ports required for connections, see Administering your instance from the web UI and Network ports.

If your Enterprise Server instance indicates that your session has expired when you connect to the Management Console through a load balancer, try one of the following configurations on your load balancer.

• Disable X-Forwarded-For headers for connections to your instance on ports 8080 and 8443.
• Configure your load balancer to operate on Layer 4, and use the PROXY protocol instead of X-Forwarded-For for passthrough of client IP addresses. For more information, see Enabling PROXY protocol support on your Enterprise Server instance.

For more information, refer to the documentation for your load balancer.

When your Enterprise Server instance is accessed via a load balancer or reverse proxy, expected live updates, such as new comments on issues and changes in notification badges or check run output, may not display until the page is refreshed. This is most common when the reverse proxy or load balancer is running in a layer 7 mode or does not support the required websocket protocol.

To enable live updates, you may need to reconfigure the load balancer or proxy. For more information, refer to the documentation for your load balancer.